Old paint -- up to five coats in some places --was stripped off each of the nine letters and a fresh layer of white paint was added.

The refurbishment, which is the most-extensive work the sign has seen in 35 years, took nine weeks to complete.

"The Hollywood Sign Trust is excited that Hollywood's leading lady received two tons of makeup in time to celebrate her 90th birthday," said Chris Baumgart, chairman of the Hollywood Sign Trust, in a press release. "We thank Sherwin-Williams for participating in this public-private partnership to restore an American icon that is recognized as a symbol of hopes and dreams around the world."

Sherwin-Williams used multiple different products to ensure the sign's new luster would live for years to come.